1. Field of the Invention
The present invention relates to an electric wire for use in winding of an electric rotating machine that constitutes an electric rotating machine winding of an AC electric rotating machine such as an electric generator or a motor. The invention also relates to a manufacturing method of an electric wire for an electric rotating machine winding and to a method for manufacturing an electric rotating machine winding.
2. Description of Related Art
In the field of an AC small-sized electric generator (hereinafter referred to as an electric rotating machine) to be mounted on an internal combustion engine installed on, for example, an automobile, ship and agricultural machine, various attempts have been made for the purpose of automating the winding operation around a stator thereof. The reason for those attempts is that it is not easy to wind a long wire around the stator starting from the end due to structure of the long wire.
For example, the Japanese Patent Publication (unexamined) No. 164043/2000 (FIGS. 2, 7, 8, 13) discloses the following method, in the case of windings being wound around a stator of a small-sized electric rotating machine as shown in FIG. 7 thereof. In this known method, coils 23, which have been formed in a U-shape as shown in FIG. 8 of the same, are sequentially fitted to the stator as shown in FIG. 13 of the same. Then end portions of the coil are machined as shown in FIG. 2 of the same, and coil ends 23d, 23f adjacent to each other are sequentially joined.
Further, the Japanese Patent Publication (unexamined) No, 211590/2001 (FIGS. 6-9), discloses the following method. In this method, long strands are folded in a thunder-shape on the same plane all together as shown in FIG. 6 of this publication, and then folded at right angles by means of a jig as shown in FIG. 7. Thus, a strand group of the inside is formed as shown in FIG. 8. Further, a strand group of the outside is formed likewise as shown in FIG. 9, and both of the inside and outside strand groups are integrally formed into a coil. The methods disclosed in the Japanese Patent Publication (unexamined) No. 164043/2000 and the Japanese Patent Publication (unexamined) No. 211590/2001 are different from each other in terms of a manufacturing method of the coil. However, from the viewpoint of connecting the end portions mutually, they are based on the same concept.
In the case of constituting a winding by the method disclosed in the Japanese Patent Publication (unexamined) No. 164043/2000 and the Japanese Patent Publication (unexamined) No. 211590/2001, a coating or film of the winding (generally composed of a resin coating film) is stripped off. Then, a notch is formed at an end portion of a conductor to form a smaller cross-sectional part. This smaller cross sectional part is utilized in order to assure that an enlarged connection portion can be inserted without fail into a narrow portion of an electric rotating machine. A stripping method of a coating 16 includes a method of a mechanical stripping such as machining, blasting or shaving, and a chemical stripping method with the use of chemicals. In addition, machining of a conductor 112 includes the methods of using a side-cutter, reamer or wire-stripper.
Even if any of the above-mentioned methods or processes is employed, in the case of the technique disclosed in the Japanese Patent Publication (unexamined) No. 1643043/2000, it is essential to conduct separately an operation of forming a notch 114 at an end portion of the conductor 112 after the operation of removing the coating 116 of an electric wire 100 has been implemented. The reason for these operations is that the same tool or machining method cannot be employed since there is any difference in shape or material intended to be machined, and the operations cannot be implemented at the same time.
Thus, it is difficult to achieve the automation by the method disclosed in the Japanese Patent Publication (unexamined) No. 164043/2000. Furthermore, even though the automation is attempted, a plurality of dedicated automatic machines that perform different operations in a dedicated manner respectively have to be used, and the operation has to undergo plural processes. As a result, a problem exits not only in higher cost but also in poor efficiency.